For many years, scientists in Leiden have been monitoring 421 exceptional families with several members who have lived beyond the age of 90. A new analysis of these extremely long-lived people and their siblings and parents now shows that longevity in these families is passed on mainly through the mother. The researchers present their results in the scientific periodical The Journal of Gerontology: Biological Sciences.

‘From our analysis of the 944 extremely long-lived men and women monitored in the Leiden Longevity Study, we know that they live longer than people born in the same year and that they are not affected by ageing diseases until later in life. We also know that their parents and siblings outlive their birth cohorts. And this despite two centuries of infections, famine and war,’ explains Eline Slagboom, leader of the research and professor of Molecular Epidemiology.

In a new analysis, PhD student Niels van den Berg found that it is the extremely long-lived mothers in particular who pass on longevity to their children, and not the longest-lived fathers. ‘Children of a long-lived mother and a non-long-lived father outlive children of a long-lived father and a non-long-lived mother, or of two parents who are not long-lived. However, this only applies to families where the mother is in the top one percent of longest survivors in her birth cohort,’ says Van den Berg. The researchers also observed that these family members’ survival advantage does not begin later in life; rather, they have a greater chance of survival than their contemporaries right from birth.

Mitochondrial DNA from the motherAccording to the researchers, the finding that longevity is passed on mainly through the mother ties in with the notion that predisposition to longevity lies in the so-called mitochondrial DNA. In contrast with the DNA in the cell nucleus, a child receives its mitochondrial DNA only from its mother, not from both parents. Another explanation is that long-lived mothers in the late nineteenth century were physically healthier and therefore had larger and healthier babies than mothers who were not long-lived. ‘We had expected the affluence of long-lived fathers in this historical period to have an impact as well, but it seems that the mother’s physiology is much more important in extreme longevity,’ explains Slagboom.

Only the best familiesThe finding brings science a step closer to the holy grail of research into ageing: identifying the genes for long life. ‘We now know even more precisely whose genes we need to map in order to find out why some people survive into extreme old age but also, and above all, why they age healthily. Lifespan in the general population is hardly ever hereditary, so our research confirms that it’s only in the rare families who have already survived longer than ordinary mortals over the past two centuries that we stand a chance of finding something,’ says Slagboom.